document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=598450>Question 598450</A>: <I><SPAN STYLE=\"word-break: break-all;\"> How many years will it take a savings bond to double in value if interest is compounded monthly at an annual rate of 4%? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #378591 by </B><A HREF=/tutors/aboutme.mpl?userid=lwsshak3><B>lwsshak3(11628)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=lwsshak3><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=378591\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> How many years will it take a savings bond to double in value if interest is compounded monthly at an annual rate of 4%?<BR>\n" );
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document.write( "compound interest formula: <BR>\n" );
document.write( "A=P(1+r)^t, P=initial investment, r=interest rate per period, t=number of periods, A=amount after t periods.<BR>\n" );
document.write( "..<BR>\n" );
document.write( "For given problem:<BR>\n" );
document.write( "A/P=2<BR>\n" );
document.write( "r=.04/12=.0033<BR>\n" );
document.write( "t=number of months<BR>\n" );
document.write( "..<BR>\n" );
document.write( "A=P(1+r)^t<BR>\n" );
document.write( "A/P=(1+.0033)^t<BR>\n" );
document.write( "2=(1.0033)^t<BR>\n" );
document.write( "take log of both sides<BR>\n" );
document.write( "log(2)=t*log(1.0033)<BR>\n" );
document.write( "log(2)/log(1.0033)=t<BR>\n" );
document.write( "using log key on calculator<BR>\n" );
document.write( "t&#8776;208 months or 17 years<BR>\n" );
document.write( " </SPAN>\n" );
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